1. Field of the Invention
Embodiments of the invention relate to the field of semiconductors, and more specifically, to clocking.
2. Description of Related Art
Standing-wave clocking offers the advantages of scalability with respect to clock frequency, low power consumption, and simplified clock system design. However, there are a number of problems of using standing-wave clocking in microelectronic high performance systems. These problems include: (1) loss-induced skew, (2) inequality of clock signal amplitudes at different clock receivers leading to skew, (3) clock phase difference of ±180° between different clock receivers, and (4) migration of voltage nodes across clock distribution points due to frequency tuning, leading to failure of the clocking system at critical clock speeds.
Existing techniques to solve the above problems are inadequate. One approach to overcome the loss-induced skew is regenerative loading of a lossy standing-wave structure for active loss compensation. This approach may have stability problems. Another approach is to place the standing-wave structure on the package where high-Q components are more readily implemented. However, this approach may hinder the testing and sorting of dies at the wafer level. Other approaches include dedicated designs supported by accurate modeling, but the resulting design complexities may be prohibitive.